Typically, banknote counting machines separate banknotes stacked or accumulated within a hopper one after the other, feed individual banknotes one by one to a counting apparatus and count the number of the banknotes therein. An example of such a banknote counting machine is described in Japanese Unexamined Patent Publication No. 6-236462 filed by the applicant.
Japanese Patent Publication No. 6-236462 details, as shown in FIG. 1, a banknote counting machine having feed-out rollers, such as a kicker roller (52) and a gate roller (53), for sequentially introducing banknotes (A) stacked or accumulated within a hopper (51); conveyance rollers, such as a feed roller (54) and acceleration rollers (55) and (56), for conveying the individual banknotes (A) which are fed by the feed-out rollers. Specifically, the banknotes stacked or accumulated within the hopper (51) are fed out from the lowermost banknote sequentially one after another by the kicker roller (52); each individual banknote is fed to the nip between the acceleration rollers (55) and (56) via the feed roller (54); the number of banknotes is counted as each banknote is passed through a non-contact optical sensor (S); and finally the banknotes are stacked or accumulated in a stacker (58) by means of a stacker fan (57). Japanese Patent Publication No. 6-236462 thus describes a machine specializing in counting the number of banknotes.
The aforementioned banknote counting machine is problem-free when there are no causes that produce feeding load in the banknote feeding path.
Recently, however, banknote counting machines also need to verify the authenticity of banknotes.
While various types of banknote authenticity verification techniques have been proposed, methods of detecting the magnetic output of magnetic ink are more commonly known. Focusing on the fact that authentic banknotes have regions printed with magnetic ink, whereas counterfeit banknotes duplicated through such methods as color copying do not, the aforementioned method uses a magnetic head to determine the presence of a magnetic field on the banknote and thereby verify its authenticity. For this purpose, a magnetic head is typically used for the detection of the magnetic ink. In such cases, however, the magnetic head has to be placed in contact with a moving banknote, which results in an increased feeding load.
For this reason, the inventors conducted various tests using the aforementioned conventional method by positioning the magnetic head in the banknote feeding path. As a result, it was found that relatively unworn or undamaged banknotes did not cause a problem, while very worn or damaged banknotes caused the magnetic head to affect the feeding load and induce paper jam.